Compared with common refractory castables, low cement or ultra-low cement castables have a series of excellent properties, which are mainly manifested in the following aspects.

Advantages of Low-Cement Refractory Castables

① Since the amount of cement added is only 1/2-1/15 of that of ordinary refractory castables, the CaO introduced into the castable is reduced from 2.5%-8% to 0-2.5%. The number of low-melting phases formed in the matrix is greatly reduced. Therefore, the refractoriness, high-temperature strength, and slag resistance are improved. The reduction of low-melting materials at high temperatures also improves the wear resistance, high-temperature flexural strength and load-softening temperature of the castable.

② The amount of water added to the mixture is only 1/2-1/3 (about 5%) of that of ordinary castables. Therefore, the porosity is low and the bulk density is high, which is comparable to the fired refractory products of the same material.

③ After molding and curing, there is little or no cement hydrate, and there is no problem of a large number of hydration bonds being destroyed during heating and baking, which affects the strength. Instead, it gradually sintered with the increase of heat treatment temperature, and the strength gradually increased. In particular, unlike ordinary castables, the mechanical strength in the medium temperature zone (900-1200℃) is higher than the drying strength. Both high temperature and room temperature strength are better than ordinary castables.

In short, low-cement and ultra-low cement castables have the advantages of high density, low porosity, good thermal strength, high refractoriness, and high softening temperature under load. Its erosion resistance is comparable to bricks of the same material, its wear rate is also significantly reduced, and its resistance to mechanical spalling and spalling is significantly improved.